The plastic industry has evolved to become one of the biggest employers of labour in many countries. Products from the plastic industry are ubiquitous and can be seen either through the end product itself or the packaging for the end product.
To keep at pace with market demands from the plastic manufacturing industry, plastic manufacturers must ensure high efficiency in their processes.
Efficiency for the plastic industry involves not only maintaining smooth operations, but an ability to offer solutions to the concerns of air quality, dust mitigation and plant efficiency.
Plastic Processing Methods
There is a wide range of methods used in plastic production. Each of the methods have advantages and disadvantages and are appropriate for specific applications. These methods include: injection molding, blow molding, thermoforming, transfer molding, reaction injection molding, compression molding and extrusion.
Injection Molding
The most well known and adopted method for plastic processing is injection molding. The process involves placing the plastic into a hopper. The hopper then transmits the plastic into a heated injection unit, where it is pushed through a long chamber with a reciprocating screw. The plastic in this avenue is softened into a molten state.
The molten plastic is then forced through a nozzle that is located at the end of the chamber into a cold closed mold. Halves of the mold are held shut with a system of clamps. When the molten plastic is cooled and solidified, the halves open and the finished product is ejected from the press.
Blow Molding
This method is adopted when a hollow plastic item is to be produced. A molten tube is created with blow molding by using compressed air, which blows up the tube and forces it to conform to the chilled mold.
The various forms of blow molding include injection blow molding, injection-stretch molding and extrusion blow molding.
Injection blow molding
Injection blow molding uses a runner (a system of channels that meet up with the sprue of the mold tool to ensure that the right design is formed in the mold tool), which is taken to a blow mold and filled with compressed air. This results in conforming to the interior design of the blow mold.
In injection-stretch blow molding, the plastic is stretched prior to being formed. This technique is what differentiates blow molding from injection molding.
Continuous-extrusion molding entails a molten plastic tube being continuously created. The tube is pinched between two mold halves at appropriate times. Then, a needle or a blow pin is inserted into the tube and blows compressed air up in order to force it to conform to the mold interior.
In accumulator-extrusion molding, the molten plastic material is collected in the chamber prior to it being forced through a small opening at the end of the chamber in order to form a tube.
Thermoforming
This method involves the use of a plastic sheet that is formed with the mold by applying air or through mechanical assistance. The air pressure used can be nearly zero psi, or several hundred psi. At 14 psi, which is equivalent to atmospheric pressure, the pressure is created by evacuating the space between the mold and the sheet.
Extrusion
This method is used for making products such as film, continuous sheeting, tubes, profile shapes, rods, coat wire, filaments, cords and cables. Similar to injection molding, extrusion involves dry plastic material being placed into a hopper and fed into a long heating chamber. The material is however forced out of a small opening at the end of the chamber in the shape of the desired finished product. As the plastic exits the small opening, it is placed on a conveyor belt where it is allowed to cool. Blowers are sometimes used to aid in this process or the product may be immersed in water to help it cool.
Health Risks Associated with Inhaling Plastic Related Dusts
Exposure to plastic dust from any of the methods described above have both short-term and long-term related health risks.
In the short-term, plastic dust exposure and inhalation can result in coughing, sneezing, eye irritation, itchy skin, headaches, breathing difficulty and mild to moderate confusion.
Health risks associated with prolonged exposure to plastic dust include occupational asthma, atelectasis, pneumonia, infertility, eczema, cardiovascular disorders, obesity, recurrent miscarriage, polycystic ovarian syndrome, occupational hearing loss, breast cancer, prostate cancer and metabolic disorders.
Problems Associated with Filtration Systems
Common problems that your plastic plant can encounter with filtration systems in dealing with dust include the following;
1. Improper Cleaning
If your filtration system does not filter properly, it can lead to high pressure drop. This may in effect, reduce the airflow at the points of dust pick-up and would lead to greater energy consumption cost.
2. Low Volume Operation
Filtration systems operating at low volume extract insufficient amounts of dust from the environment. This results in the loss of valuable time and money to your company.
3. High Volume Operation with Excessive Extraction
When your filtration systems operate excessively, they absorb not only dust in the workspace but also other products and fresh air that is needed for healthy breathing. This subjects your plant to fresh air insufficiency. When your filtration system removes more than what is desired, it can cost your plant and employees losses.
4. Excessive Leakage
Your filtration system must be able to pick up dust and vent it into the atmosphere without problems. Excessive leakages from your filtration system inhibits harmful dust from being expelled, thereby making inhalation of toxic plastic dust available to workers working in your plant.
Envirox Solutions for Plastic Dusts Generated in Plastic Processing Plants
FMC
Our FMC filters are well designed filter systems for absolute collection of dusts from workspaces to ensure continuous availability of fresh air and to prevent equipment and machineries from being damaged by dust particles.
The FMC filter systems are suited for air volumes between 3200 – 21200 m3/h containing different types of dust particles.
The modular compact design of Nederman FMC supplied by Envirox can be installed close to the source of dust generation. This provides a solution in ensuring that dusts are extracted immediately as they are produced, and also reduces your energy consumption.
You can also use different types of cartridges on our FMC dust collectors and it will surely deliver the desired result.
Our FMC dust collector meets all ATEX compliant standards for all forms of combustible dusts.
FilterBox with HEPA Filter
The filterBox unit is an advanced filter control system with automatic cleaning that starts when the airflow is too low.
Our FilterBox unit provides additional protection from harmful dust particles when HEPA filters are installed with it.
FilterBox supplied by Envirox has a powerful fan for maximum airflow capacity of 1200m3/h.
Our FilterBox system is available in mobile unit on wheels and can be attached to a floor stand.
The FilterBox has an automatic damper that prevents dust leakage when cleaning.
Modular Filter System (MFS)
MFS is an ideal dust extraction system designed to capture dusts at source of production in your plastic processing plant. It solves the problems of ridding the air of particles, smokes, dusts and fumes and foul odours so as to ensure a safe and conducive working environment for your employees.
You can set MFS up for multiple arms. This guarantee that you can rapidly collect and filter dust from your plant in all directions.
MFS supplied by Envirox can be supplemented with a fan, extraction arm and control box, which makes it suitable for every plastic processing workplace.
Original Arms for At-Source-Extraction
The original arm is a patented design that is easy to maneuver for optimal dust collection.
The extraction hood of our original arm has integrated easy-to-reach buttons for lighting and fan control as optional feature.
Original arms supplied by Envirox is a perfect solution with different brackets, extension arms, exhaust rails or on fixed portable filter equipment.
The original arm is also equipped with damper in the hood as standard.